This disclosure relates, in various embodiments, generally to image producing machines, and more particularly to a solid ink imaging machine having an intermediate transfer surface and an intermediate transfer surface maintenance system.
In general, phase change ink image producing machines or printers employ phase change inks that are in the solid phase at ambient temperature, but exist in the molten or melted liquid phase (and can be ejected as drops or jets) at the elevated operating temperature of the machine or printer. At such an elevated operating temperature, droplets or jets of the molten or liquid phase change ink are ejected from a print head device of the printer onto a print drum or belt that can then be transferred directly onto a final image receiving substrate. In any case, when the ink droplets contact the surface of the substrate, they quickly solidify to create an image in the form of a predetermined pattern of solidified ink drops.
An example of such a phase change ink image producing machine or printer, and the process for producing images therewith onto image receiving sheets is disclosed in U.S. Pat. No. 5,372,852 issued Dec. 13, 1994 to Titterington et al. As disclosed therein, the phase change ink printing process includes raising the temperature of a solid form of the phase change ink to melt it and form a liquid phase change ink. It also includes applying droplets of the phase change ink in a liquid form to an intermediate transfer surface on a solid support in a pattern using a device such as an ink jet print head. It then includes solidifying the phase change ink on the intermediate transfer surface, transferring the phase change ink from the intermediate transfer surface to the substrate, and fixing the phase change ink to the substrate.
Conventionally, the solid form of the phase change is a “stick”, “block”, “bar” or “pellet” as disclosed for example in U.S. Pat. No. 4,636,803 (rectangular block 24, cylindrical block 224); U.S. Pat. No. 4,739,339 (cylindrical block 22); U.S. Pat. No. 5,038,157 (hexagonal bar 12); U.S. Pat. No. 6,053,608 (tapered lock with a stepped configuration). Further examples of such solid forms are also disclosed in design patents such as U.S. Pat. No. D453,787 issued Feb. 19, 2002. In use, each such block form “stick”, “block”, “bar” or “pellet” is fed into a heated melting device that melts or phase changes the “stick”, “block”, “bar” or “pellet” directly into a print head reservoir for printing as described above.
The quality of the images produced by phase change ink image producing machines or printers depends in part on how well the print drum or belt is maintained by a drum maintenance system, i.e., how well any residues are cleaned from the print drum and how evenly a release oil is applied to the print drum. Such quality also depends on the print drum and its surface finish or texture, the print heads, and the image receiving substrates. Many such image producing machines have adjustable parameters which can improve the cleaning effectiveness of the drum maintenance system. However, setting or adjusting of these parameters is performed either on a scheduled basis, or only after the quality of the printed images is observed to be deteriorating.
There is therefore a need for a system and method for automatically monitoring the performance of the drum maintenance system and adjusting parameters of the drum maintenance system to maintain the quality of the printed images automatically.